1. Field of the Invention
This invention generally relates to daisy wheel printers. More specifically, this invention relates to a cartridge for housing a daisy wheel print element during both storage and use in a printer.
2. Description of the Prior Art
Representing other work in this same area is U.S. patent application Ser. No. 767,250, filed Feb. 10, 1977, now U.S. Pat. No. 4,127,335, having Bogert et al. as inventors and entitled "Impact Printer With Cartridge Print Wheel". In this referenced application is disclosed a cartridge for housing a daisy wheel print element. There are a number of notable similarities between the instant and referenced applications. Both generally disclose (1) a shell within which a print element is fitted and which is to be received by a printer carrier mechanism with minimum operator intervention, (2) a generally centralized opening within the front of the shell through which access to the print element is provided for a selection motor drive hub, (3) a print hammer slot in the top of the front of the shell, and (4) a retaining leaf spring in the back of the cartridge which also serves as a bearing surface for the print element.
Several of the more important distinctions between the two applications and the advantages thereof as related to the instant application will now be addressed. To begin with, the cartridge of the instant application substantially totally encloses the print element. The only area of the print element which is readily accessible to an operator when the element is housed in the cartridge is that adjacent the centralized opening. The advantage of this is a reduced chance of soiled hands. The leaf spring in the instant application has a center bow and is oriented in the direction of insertion and removal of the print element. The centralized opening in the instant application matches an orientation protrusion on a print element and when both are in engagement, the spring serves to maintain the print element in a latched and desired rotational position for acceptance by a printer. Further, during insertion of the print element into the cartridge, the leaf spring serves as a ramp to cam the orientation protrusion toward the orientation opening. Also, the leaf spring is of a sufficient width relative to the orientation opening to prevent a print element petal from extending through the orientation opening during insertion of the element into the cartridge.
The above, as well as other distinctions and advantages of the instant application over the referenced application will be more fully appreciated when reference is made to the accompanying drawing and following description of the preferred embodiment.